Every generic OBD-II code in plain language: what the code means, what you will notice when it appears, the parts that actually cause it, and whether it is safe to keep driving. 76 codes published, all from the SAE J2012 / ISO 15031-6 generic definitions that every manufacturer follows.
The codes below are legally mandated and mean the same thing on every car. A code like P0301 is a cylinder 1 misfire whether the car is a Honda or anything else. Manufacturer-specific codes (the ones starting P1xxx for a particular brand) are not listed here, because their meaning differs per manufacturer and we will not publish a definition we cannot verify.
| P0xxx | Powertrain — engine, transmission, emissions. The most common family. |
|---|---|
| P2xxx | Powertrain, manufacturer-specific numbering. |
| B0xxx | Body — airbags, climate, lighting, comfort systems. |
| C0xxx | Chassis — ABS, suspension, steering. |
| U0xxx | Network — communication between control modules. |
P0562 System Voltage LowRepair soonP0563 System Voltage HighRepair soonP0600 Serial Communication Link MalfunctionRepair soonP0601 Internal Control Module Memory Check Sum ErrorRepair soonP0606 Control Module Processor FaultRepair soonP0401 Exhaust Gas Recirculation Flow InsufficientLow urgencyP0402 Exhaust Gas Recirculation Flow ExcessiveLow urgencyP0411 Secondary Air Injection System Incorrect FlowLow urgencyP0420 Catalyst System Efficiency Below Threshold (Bank 1)Low urgencyP0430 Catalyst System Efficiency Below Threshold (Bank 2)Low urgencyP0440 Evaporative Emission Control System MalfunctionLow urgencyP0442 Evaporative Emission Control System Leak Detected (Small Leak)Low urgencyP0455 Evaporative Emission Control System Leak Detected (Large Leak)Low urgencyP0456 Evaporative Emission Control System Leak Detected (Very Small Leak)Low urgencyP0100 Mass Air Flow Circuit MalfunctionRepair soonP0101 Mass Air Flow Circuit Range/PerformanceRepair soonP0102 Mass Air Flow Circuit Low InputRepair soonP0103 Mass Air Flow Circuit High InputRepair soonP0106 Manifold Absolute Pressure Circuit Range/PerformanceLow urgencyP0110 Intake Air Temperature Circuit MalfunctionLow urgencyP0112 Intake Air Temperature Circuit Low InputLow urgencyP0113 Intake Air Temperature Circuit High InputLow urgencyP0115 Engine Coolant Temperature Circuit MalfunctionRepair soonP0116 Engine Coolant Temperature Circuit Range/PerformanceLow urgencyP0117 Engine Coolant Temperature Circuit Low InputRepair soonP0118 Engine Coolant Temperature Circuit High InputRepair soonP0120 Throttle Position Sensor Circuit MalfunctionRepair soonP0121 Throttle Position Sensor Range/PerformanceRepair soonP0122 Throttle Position Sensor Circuit Low InputRepair soonP0123 Throttle Position Sensor Circuit High InputRepair soonP0128 Coolant Thermostat Below Regulating TemperatureLow urgencyP0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)Repair soonP0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)Repair soonP0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)Repair soonP0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)Low urgencyP0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)Repair soonP0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)Low urgencyP0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)Low urgencyP0170 Fuel Trim Malfunction (Bank 1)Repair soonP0171 System Too Lean (Bank 1)Repair soonP0172 System Too Rich (Bank 1)Repair soonP0174 System Too Lean (Bank 2)Repair soonP0175 System Too Rich (Bank 2)Repair soonP0200 Injector Circuit MalfunctionRepair soonP0230 Fuel Pump Primary Circuit MalfunctionRepair soonP0234 Turbocharger Overboost ConditionRepair soonP0299 Turbocharger UnderboostRepair soonP0300 Random or Multiple Cylinder Misfire DetectedDo not keep drivingP0301 Cylinder 1 Misfire DetectedDo not keep drivingP0302 Cylinder 2 Misfire DetectedDo not keep drivingP0303 Cylinder 3 Misfire DetectedDo not keep drivingP0304 Cylinder 4 Misfire DetectedDo not keep drivingP0305 Cylinder 5 Misfire DetectedDo not keep drivingP0306 Cylinder 6 Misfire DetectedDo not keep drivingP0325 Knock Sensor 1 Circuit MalfunctionLow urgencyP0335 Crankshaft Position Sensor A Circuit MalfunctionDo not keep drivingP0340 Camshaft Position Sensor A Circuit MalfunctionRepair soonP0351 Ignition Coil A Primary/Secondary CircuitRepair soonP0352 Ignition Coil B Primary/Secondary CircuitRepair soonU0001 High Speed CAN Communication BusRepair soonU0100 Lost Communication With ECM/PCM ADo not keep drivingU0101 Lost Communication With Transmission Control ModuleRepair soonU0121 Lost Communication With ABS Control ModuleRepair soonU0140 Lost Communication With Body Control ModuleRepair soonU0155 Lost Communication With Instrument Panel ClusterRepair soonP0500 Vehicle Speed Sensor MalfunctionRepair soonP0505 Idle Control System MalfunctionRepair soonP0507 Idle Control System RPM Higher Than ExpectedLow urgencyP0700 Transmission Control System MalfunctionRepair soonP0715 Input/Turbine Speed Sensor Circuit MalfunctionRepair soonP0720 Output Speed Sensor Circuit MalfunctionRepair soonP0730 Incorrect Gear RatioRepair soonP0740 Torque Converter Clutch Circuit MalfunctionLow urgencyP0741 Torque Converter Clutch Circuit Performance or Stuck OffLow urgencyP0750 Shift Solenoid A MalfunctionRepair soonP0755 Shift Solenoid B MalfunctionRepair soon